The “next generation” particle accelerator, expected to be up and running by 2025, will cost around £8bn and like the LHC it will be an international collaboration.

Instead of whirling atoms in giant rings like at Cern in Switzerland , the linear collider will fire them in straight lines along a 31-mile track.

It will probe:

The possibility of powerful extra dimensions “hiding” at an ultra-tiny scale alongside the visible.

The theory of Supersymmetry, a world of super particles that partner the elementary particles we know today.

The nature of dark matter, astonishingly, scientists have found 96% of the universe is not made up of ordinary matter but 76% dark energy and 22% dark matter. Even though we can’t see it, without it the Earth would fly off into the coldness of deep space.

String theory, that suggests sub-atomic particles are not fixed entities but can be, say, photons (light particles) one second and quarks (atoms’ fundamental building blocks) the next in a kind of cosmic symphony.

Cern experts say the new linear collider will be a “scalpel” examining newly discovered particles chipped off atoms by the LHC which was launched with great fanfare by Dr Evans in September 2008.

The former Swansea University physics graduate and father of two grew up in a council house in Cwmbach, Aberdare and went to Aberdare Grammar School.

He now lives on the outskirts of Geneva with his wife Linda where he says he misses going to watch Welsh rugby.

He spent 16 years as project director of the LHC, retiring two years ago after the 17-mile ring of super-cooled magnets which fires particles at each other as near light speeds, was up and running smoothly.

This week he hailed the LHC’s apparent success in doing what it was designed to do, find the elusive Higgs Boson, the previously theoretic “God Particle” predicted by Professor Peter Higgs which explains why all particles have mass.

If it had not been found (Cern is 99.9% certain it has been detected), modern science’s so-called “standard model” of what the universe is made of would have been consigned to the rubbish bin.

For several years, the world’s particle physics community has been developing proposals for the next step – the International Linear Collider, ILC, and the Compact Linear Collider, CLIC.

Dr Evans, now 67, has come out of retirement to lead the effort to unify the two projects and represent the combined effort to the worldwide science community and funding agencies.

He has been appointed Linear Collider Director by the International Committee for Future Accelerators (IFCA), the body responsible for the new collider.

Depending on who wants to host it – and how much they are willing to pay – the new machine could potentially be built anywhere in the world.

Before flying to Australia this week to further the project, Dr Evans told Wales on Sunday: “It’s going to be one of the biggest scientific experiments of the 21st century.”

While the LHC and the Linear Collider are more about shaping our understanding of how the universe was created than immediate improvements to our daily lives, the work at Cern has already led to technologies such as the world wide web, PET scanners and proton beam cancer therapy.

“The international particle physics community is fortunate to have Lyn at the helm of this new organisation,” said ICFA chair Pier Oddone.

He added: “He brings tremendous experience to the position, having led the construction of the Large Hadron Collider that is already exceeding performance expectations after only a short time in operation.”

“We expect Lyn will ably lead the way in developing a reliable, viable proposal for a future linear collider,” said previous ICFA Chair Atsuto Suzuk.

Dr Evans said of the project: “The work at the LHC was criticised for its cost but it was an international project that brought together scientists from all kinds of divides and appears to have delivered results.

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